Vehicle and method of coordinated lash management

Abstract

A method of controlling a change in net axle torque on a vehicle comprises receiving a request for a desired net axle torque that is different than a current net axle torque, determining whether a lash zone exists between the current net axle torque and the desired net axle torque, determining a progression of constant rates of change of the front axle torque and a progression of constant rates of change of the rear axle torque that will result in a constant rate of change of the net axle torque from the current net axle torque to the desired net axle torque, and commanding the progression of constant rates of change of the front axle torque and the progression of constant rates of change of the rear axle torque if the lash zone exists between the current net axle torque and the desired net axle torque.

Description

INTRODUCTION[0001]The disclosure relates to a vehicle and a method of controlling net axle torque on a vehicle.[0002]Vehicle drive trains may experience lash when a vehicle axle responds to a commanded change in torque. Lash may be characterized as a sharp increase in the frequency of angular rotation and associated torque discontinuities at a vehicle axle when commanded torque provided by a prime mover and the wheel torque, or road load torque, change direction from one another such as due to a driver-commanded change in acceleration. Lash may be due to lost motion resulting from clearances between components in the drivetrain. Lash may be experienced by a driver as a delay in response (referred to as a dead zone or dead pedal) and / or an audible clunking and / or jerkiness that may occur as drivetrain components respond to the change in rotational force.SUMMARY[0003]A method of controlling net axle torque on a vehicle is disclosed that enables a constant rate of change in net axle to...

AI Technical Summary

Benefits of technology

The patent describes a method to control the torque on a vehicle's axles to minimize the effects of lash, which is when there is space between the axles. The method involves coordinating the torque provided by the vehicle's prime movers in real-time to achieve a smooth and constant change in the overall net axle torque. By doing so, the vehicle can transition through the lash zone without causing any sudden jerk movements. The technical effect is to improve the stability of the vehicle's axles during operation.

Problems solved by technology

Lash may be due to lost motion resulting from clearances between components in the drivetrain.

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